ᐅ Cost Estimation of a Prefabricated House

So, thanks for the responses and suggestions.

1) We will not undertake any self-performed work.
2) Basement construction > see text further below.
3) The children's room also has access to the master bathroom according to the floor plan. Maybe the wording was not quite right.

-----SEPARATION-----

We had our initial meeting today.

We were shown a 3D floor plan that presents the utility room in the garage extension as one option.
This way, no space on the foundation slab is lost, and the ground floor room can even be used as a guest room. So, we are actually avoiding basement construction.
The roof structure can be easily accessed as it will be 190cm (75 inches) high.
Also, no construction contract has been presented to us yet.

In September, we will do a trial overnight stay in one of their show homes and at the same time review preliminary selections to better estimate costs and observe the production.
Furthermore, we scheduled an appointment to visit a FischerHaus construction site during the shell construction phase.

Payment terms are regulated as follows:
5% of the contract amount upon house order
65% of the contract amount after house erection
30% upon key handover

He also broke down the costs based on the floor plan.
KfW40 standard house, turnkey. 146sqm (1570 sq ft), 2096 €/sqm = 306,083 €

Total: 306,083 €


Special requests without selections.
Exterior venetian blind 1.10 x 1.19 m (3.6 x 3.9 ft): 6 * 354 € = 2,124 €
Exterior venetian blind 0.72 x 0.865 m (2.4 x 2.8 ft): 1 * 295 € = 295 €
Exterior venetian blind 1.975 x 2.11 m (6.5 x 6.9 ft): 6 * 644 € = 3,864 €
Loxone intercom: 1 * 1,883 € = 1,883 €
Double vanity including connections: 1 * 1,500 € = 1,500 €
Heating with cooling function: 1 * 1,945 € = 1,945 €
Rain shower: 1 * 800 € = 800 €
Terrace sliding door 3.97 x 2.11 m (13.0 x 6.9 ft): 1 * 2,070 €
Adjustable and dimmable spotlights including installation + wiring: 37 * 107 € = 3,959 €

Total: 18,440 €


All other items can be purchased through FischerHaus or contracted independently.
He provided us with experience-based figures to help with better cost estimation.
Photovoltaic system: 6.12 kWp + battery storage 5.5 kW = 20,916 €
Foundation slab: 95sqm (1023 sq ft), 218 €/sqm = 20,708 €
Excavation work: 20,000 €
Soil survey report: 1,500 €
Surveying: 2,000 €
Building permit / planning permission: 3,221 €
House connections (telecommunications, electricity, wastewater, rainwater, fresh water): 12,000 €
Other incidental costs (construction power, construction water, insurance, etc.): 1,000 €
Double garage: 6 x 9 m (19.7 x 29.5 ft), 2 parking spaces, 15,500 € each = 31,000 €
Garage substructure: 54sqm (581 sq ft), 100 €/sqm = 5,400 €
Outdoor landscaping: approx. 5% of house price = 15,304 €

Total: 133,049 €

Overall, if we build like this, the calculation does not fit within our budget framework.
Therefore, we will receive a revised offer for a single-family house of 130sqm (1,399 sq ft).
Here and there, we are also considering possibly adding some items at a later stage, for example:
- Cooling function for the air-source heat pump (apparently feasible)
- Garage
- Outdoor landscaping
- Reducing the number of spotlights
- Ground floor exterior venetian blinds, upper floor roller shutters
- Photovoltaics
- Battery storage
- Smart home system
- A smaller terrace sliding door

Alternatively, we might be able to increase our budget with the bank, but this still needs to be clarified.

I can imagine that both downsizing and trimming down certain areas might be necessary to stay within budget. However, I still believe that implementing the planned room layout will be challenging with at least 130 square meters (1,400 square feet). If the utility room is moved to the garage extension, it does free up space inside the house, but the technical room will need to be upgraded since it cannot be used as is for that purpose. So, it probably won’t save much money—and you lose the space in the garage extension.

Would you be willing to share the current floor plan? Or have I simply missed it so far?

I don’t think the budget will be enough, but you can probably tell that already from the initial consultation.
We are currently building in a rural area, with 133 sq m (1,433 sq ft) plus about 25 sq m (269 sq ft) of almost finished attic space and a double garage, and our costs have already reached the five-figure range, even though our plot was one-third cheaper. We only have one external venetian blind over a 4-meter (13-foot) front, a 7.4 kW photovoltaic system without battery storage, KfW 55 energy standard, and no smart home system—just the basic Merten Wiser alternative that controls the roller shutters and three light switches. We do have some spotlights, but they are surface-mounted. We are doing the landscaping ourselves, and material costs are already over 10,000.00.

TangoDeltaLima schrieb:

He also broke down the costs for the floor plan.
KfW 40 house, turnkey. 146 sqm (1571 sq ft), €2096/sqm (€195/sq ft) = €306,083

TangoDeltaLima schrieb:

€

Custom requests without selection process.
External venetian blinds 1.10 x 1.19 m (3.6 x 3.9 ft): 6*€354 = €2,124
External venetian blind 0.72 x 0.865 m (2.4 x 2.8 ft): 1*€295 = €295
External venetian blinds 1.975 x 2.11 m (6.5 x 6.9 ft): 6*€644 = €3,864
Loxone intercom: 1*€1,883 = €1,883
Double washbasin including connections: 1*€1,500 = €1,500
Heating with cooling function: 1*€1,945 = €1,945
Rain shower: 1*€800 = €800
Terrace sliding door 3.97 x 2.11 m (13.0 x 6.9 ft): 1*€2,070 = €2,070
Swiveling and dimmable spotlights including installation and wiring: 37*€107 = €3,959

Total: €18,440

Cool!
My calculation matches that of the builder’s representative, even though I calculate a bit differently as a layman:

€2,100/sqm (195 sq ft) living area
€20,000 for custom features
€70,000 for basement
€60,000 for technical upgrades (KfW 40 standard, photovoltaic system, smart home, etc.)

I’d say your requests are somewhat coming from the “I-want-it-all” category.
There’s a reason why some houses look rather “bare” inside and out to others, or why a standard light switch is enough. Also, most wouldn’t have to debate the pros and cons of a basement if the budget were unlimited or if the basement came at no cost. As living space expansion, add another one-third on top.
Skip the fancy freezer features, those can be added later. The basement also costs more than it brings in benefits—an expanded attic might be a better option for extra rooms.
I remember someone here dreaming about a hookah lounge in the basement, Grym or Baugrym… a cool man cave… in the end, they built without fuss and no basement: once you have children, you don’t really have time for that anyway.

TangoDeltaLima schrieb:

Cooling function heating system: 1*1945 € = 1945 €

A house seller once told us that reversible heat pumps and ventilation systems are not compatible with KfW 40 Plus standards. I have no idea if that is actually true.

TangoDeltaLima schrieb:

Photovoltaic system: 6.12 kWp + battery storage 5.5 kW = 20916 €

The photovoltaic system is too small, or the battery storage too large. Besides, the system is far too expensive.

TangoDeltaLima schrieb:

Double garage: 6x9 m (20x30 ft), 2 parking spaces, at 15,500 € each = 31,000 €
Garage substructure: 54 sqm (581 sq ft), 100 € = 5,400 €

Our single garage with a 7 sqm (75 sq ft) adjoining storage room costs 38,000 €. I find 36,400 € for a double garage a bit low. How is it supposed to be built? Attached directly to the house or separately (= prefab garage)?

You are tight on budget but want KfW 40 standard, which I have never understood. By the way, a technical room located outside the building envelope is not allowed.